The context menu on items "Take -> Lock to active take" doesn't in fact lock the take, it toggles the lock state.
If I select several take items, if some are locked and other are not, it will toggle the lock state, while I guess most users (at least me) would expect it to lock or unlock all.

What would be great is adding a 3-state checkbox in front of it (none, black or grey) which reflect the current take items lock state.
If the state is multiple (grey), it would set all items to a lock state.
If none are locked, it would lock all
If all are locked, it would unlock all.

Or keep the actual checkbox behaviour (no check if not all items are locked) and lock all if at least one is not, or unlock all.

You can go to "Actions"→"Show Action List" and search for "lock to active take" (just entering "lock" will suffice), and set a hotkey to this action. This one doesn't toggle, this one actually locks all selected items to active take, and doesn't affect the ones that are already locked. What I do then is just select all takes in my session, and hit the hotkey. And that's it, everything is locked, no more accidental take switching.

PS. I know, it's an old thread, but it's my third time googling it up due to the similar issue, so I thought to post my solution here. Might be useful to someone.